Basketball mechanic in a baseball game?

[Mark Padgett]

I was watching the Astros - Scrubbies (that's what us Chicago south siders call that team from the north side) game today and with 2 out and runners on first and second, the second base umpire looked at the first base ump and gave the "intentional foul" signal - i.e. he crossed his arms out in front of his chest. Maybe one of you multi-sport officials can explain.